Magnetic separator with stationary magnet



July 28, 1953 D. w. MOLINS ET AL MAGNETIC SEPARATOR WITH STATIONARYMAGNET 4 Sheets-Sheet 1 Filed July 12, 1949 July 28-, 1953 D. w. MOLINSET AL MAGNETIC SEPARATOR WITH STATIONARY MAGNET v 4 Sheets-Sheet 2 FiledJuly 12, 1949 July 28, 1953 D. w. MOLINS ETAL 2,646,883

' MAGNETIC SEPARATOR WITH STATIONARY MAGNET I Filed July 12, 1949 4Sheets-Sheet s July 28, 1953 D. w. MOLINS ET AL 2,646,833

MAGNETIC SEPARATOR WITH STATIONARY MAGNET Filed July 12, 1949 4Sheets-Sheet 4 Patented July 28, 1953 MAGNETIC SEPARATOR WITH STATIONARYMAGNET Desmond Walter Molins, Felix Frederic Ruau, Valentine PearceHarvey, and Sydney Alfred Nichols, Deptford, London, England, asslgnorsto Molins Machine Company, London, England,

a British company Application July 12, 1949, Serial No. 104,234 In GreatBritain July 27, 1948 6 Claims. 1 This invention concerns improvementsin or relating to magnetic separators and more particularly separatorsfor removing a relatively small quantity of paramagnetic material from alarge mass of other material. An example of such a separator is themagnet system used in cigarette 'making machines for removing particlesof'iron,

nails, screws and the like from the tobacco as it passes along on aconveyor, such as a carded roller. In time, some quantity of iron iscollected on the magnets and it is necessary to remove this and hithertothis has been done by shifting the magnets from their operative positionand wiping them. This is an awkward operation and may involve stoppingthe machine for the sake of safety.

According to the present invention there is provided a separator oi thekind referred to comprising a shield or facing of non-magnetic materialcovering the magnets during the separating operation, means for movingthe magnets and shield, to a non-operative position and means for'thereafter'removing the shield out of the magaway from the magnets. L

Two ways of carrying the invention into elTect will be described withreference to the accompanying drawings which show its application to thetobacco hopper of a cigarette-making machine.

In the drawings:

Figure l is a front elevation (shown broken) of the device installed inthe hopper.

Figure 2 is a side elevation of Figure 1 in the direction of arrow Awith the hopper side at the end adjacent the arrow shown in chain lines.

Figure 3 is a section of part of a tobacco hopper showing a modifiedform of the invention;

Figure 4 is a view of part of Figure 3 looking in the direction of thearrow B.

Like references refer to like parts in all four figures.

Referring to Figures 1 and 2 of the drawing,

' a row of permanent magnets l are positioned above and along theperiphery of a roller 2 (which is omitted fromFigure 1) and whichconveys the tobacco. The roller is carded but thecarding is 2 omitted inFigure 2 and the roller is identical with that shown in Figure 3.

The magnets are so disposed that the faces of their poles are normal toa radius of the roller and the'magnets are supported on a rod 3journalled in bearings Q on the side frames 5 of the hopper so that byrotating the rod the magnets can be moved to a non-operative position. Ashield E5 of non-magnetic material is attached to the magnets and is ofL section, one arm of the L lying close to the poles and the other armextending along one side of the magnets. The end of the second arm ofthe L is pivoted at 1 so that the shield can be swung about the pivotagainst the action of springs 26 and away from the magnets. A pin orabutment 8 is fixed at each end of the shield near the angle of the L sothat pressure on said pins will rotate the shield on its pivots andswing the shield away from the magnets.

A trough 9 is provided and pivoted at [0 so that it can swing from itsnormal position to a position where it extends beneath the shield 6 andcan receive material falling therefrom, and on each end of the trough isa pawl H or the like adapted to engage the corresponding pin 8 on theshield and cause the latter to swing away from the magnets.

When the magnets are in the operative position, as shown inFigure 2paramagnetic material removed from the tobacco on the carded roller 2 bythe magnets naturally adheres to the face of the shield. When it isdesired to clean the shield of such material a lever I2 is moved to theposition shown in chain lines in Figure 2 whereby the magnets and theshield are caused to swing around the pivots of the rod 3, and broughtto a non-operative position. Another lever I3 is then manipulated toswing the trough about its pivots ID from its normal position, Figure 2,to the receiving position beneath the shield 65, the latter elementbeing then in the chain line position shown, and during this movementthe pawls II on the trough encounter the pins 8 on the shield 8 andcause the latter to swing on its pivot 1 away from the magnet. The partsare so shaped and timed that the shield moves well within the confinesof the trough before the shield is far enough away from the magnets forthe paramagnetic material to be sufiiciently free of the magnetic fieldfor the material to drop from the shield. In this'way all the materialis safely caught in the trough and cannot fall back on to the cardedroller in which case it might pass into the rod forming apparatus of themachine and cause damage.

The free edgeof the part of the shield which lies close to the poles ofthe magnets is curved or bent outwardly to form a lip M. The purpose ofthis is to prevent particles of paramagnetic material from running offthe shield on to the magnets under the influence of the magnetic field,while the shield is being swung towards its inoperative position.

While the arrangement described for moving the trough and shield is veryconvenient, it will be seen that according to the kind of machine inwhich the separator is employed,- it may be desirable to modify thedesign, and this may be done without departing from the scope 6f theinvention.

The lever 12 is held in the chain line position by a latch l pivoted atHi. This latch is released manually when it is desired to return themagnets to the operative position. During the swinging movement of thetrough it is guided by pins I! fixed to the pawls l l which run in slots58 formed in quadrants i9 screwed to the hopper walls. A torsion spring29 holds the trough 5 iii the inoperative position. When there issufficie'nt material in the trough 9 to warrant emptying it, it islifted off its pivots M3, for as may be seen from Figure 2 the part ofthe trough which engages the. pivots is slotted.

It will be seen however, from Figure 1, that the lever I3 is permanentlyattached to the pivot side by its pivot pin 22'. In order therefore, toallow the trough to be removed as stated, a crank 23 is fixed on theinner end of the pin 22 and at the free end thereof is a crank pin 24whichworks inan open-ended slot 28 in a plate 28 which is riveted to theend wall of the trough Q.

In an alternative construction shown in Figures 3 and 4 which isdesigned for use with a dififerent kind of hopper in which there is lessroom for moving the magnets and associated parts, the magnets arecarried on two links 25 and 2B, pivoted. at 21 and 28' respectively,whereby they can, by/a swingingmovement of the links, be moved in thedirection of the arrow and away from the carded roller to anon-operative position. ihe reason for this arrangement is that in thishopper it is necessary to arrange for magnets to extend. between twosmall rollers and 3| adjacent the carded roller 2 and it is thusnecessary to withdraw the magnets rearwardly to avoid fouling. theroller 39 and the parts shown above the roller 3| The links are soarranged that the magnets move almostin a straight line radialto thecardedro-ller. On of the links carries a pawl 32 arranged to engage pin33 on the nonmagnetic shield for the purpose of swinging it away as inthe construction previously described. Due to the arrangement of thelinks the pawl overtakes the pin 33 while the magnets are moving awayfrom the carded roller but does not engage the pin until the magnets areclear of the small rollers; Thus the shield remains in position unitlthe magnets are clear, being held in position by the spring 2|. A trough34 is located in the hopper in a suitable position such that the shieldisabove the trough by the time it has been swung away from the magnets asufficient distance for the paramagnetic material adhering to the shieldto be free of the magnetic field. The trough in this case is stationary,so far as any automatic operation is concerned and supported on pins 3-5fixed to the hopper side, but it is, arranged so as, to be easilydisplaceable removable for emptying from time to time. A stop 36 on thelever 26 limits the magnets move- ;ment by. engagement with the lever25-.

What we claim as our invention and desire to secure by Letters Patentis:

1. In a magnetic separator of the class de scribed, in combination, asupporting frame, at least one separating magnet, a surface movinrelative to said magnet and providing a conveyor for material from whichextraneous magnetic bodies are to be extracted, displaceable means forsecuring said magnet to said supporting frame for adjustment to and froma position adacent said conveyor surface where the passing material isin the field of attraction of said magnet and such bodies are attractedto the magnet and separated from the mass of material, means fordisplacing said first named means for moving said magnet away from saidconveyor surface, a non magnetic shield distinct and separate from theconveyor surface and covering said magnet during the separatingoperation whereby said bodies adhere to said shield while it remains inmagnet covering position, a displaceable trough carried by saidsupporting frame, one of the positions of said trough being that inwhich it is disposed beneath the magnet and shield when the lattermembers are moved away from the conveyor surface, and means associatedwith said shield and automatically operable upon abutment with one ofthe above recited displaceable parts of the separator to remove theshield out of the field of the magnet while the shield is above thetrough, whereby any paramagnetic bodies adhering to the shield fall awaytherefrom.

2. A separator as set forth in claim 1 in which the last named meansincludes a projection on said shield which is adapted to be contacted byan element associated with and movable simultaneously with said trough.

3. In a magnetic separator of the class described, in combination, asupporting frame, at least one separating magnet, a surface movingrelative to said magnet and providing a conveyor for material from whichextraneous magnetic bodies are to be extracted, displaceable means forsecuring said magnet to said supporting frame for adjustment to and froma position adjacent said conveyor surface, upon the opposite side of themass of material thereon from said surface and so that the passingmaterial is in the field of attraction of said magnet and such bodiesare attracted to the magnet and separated from the mass of material,means for displacing said first named means for swinging said magnetaway from said conveyor surface, a non-magnetic shield covering saidmagnet during the separating operation whereby bodies adhere to saidshield while it remains in magnet covering position, a displaceabletrough carried by said supporting frame, one of the positions of saidtrough being that in which it is disposed beneath the magnet and shieldwhen the latter members are swung away from the conveyor surface, andspring means for r'esiiiently and yieldably urging said shield intocovering relationship with said magnet, a projection on said shieldadapted to abut one of the above recited displaceable parts of theseparator to remove the shield out of the field of the magnet while theshield is above the trough, whereby any paramagnetic bodies adhering tothe shield fall away therefrom.

4. In a magnetic separator of the class described, in combination, asupporting frame, at least one separating magnet, a surface movingrelative to said magnet and providing a conveyor for material from whichextraneous magnetic bodies are to'be extracted, means for displaceabl-ysaid magnet and such bodies are attracted to the magnet and separatedfrom the mass of material, means for moving said magnet away from saidconveyor surface, a non-magnetic shield covering said magnet during theseparating op eration whereby said bodies adhere to said shield while itremains in magnet covering position, said magnet securing meanscomprising two side-byside links having their adjacent remote endspivoted to the supporting frame at a fixed distance apart and theiropposite ends pivotally connected to spaced points on the magnet,thereby providing an approximate parallel-motion linkage support, thesaid support being thus arranged to swing said magnet approximately in astraight line normal to the conveyor surface.

5. A separator as set forth in claim 4 in which the conveyor surface isthat of a cylinder and the path of movement of said magnet issubstantially radial thereto.

6. A separator as set forth inclaim 4 in which the link which is leadingas the magnets move toward non-operative position provides an abutmentadapted to engage the following link toward the end of the movement andarrest the magnet in the desired remote position.

DESMOND WALTER MOIENS. FELIX FREDERIC RUAU. VALENTINE PEARCE HARVEY.SYDNEY ALFRED NICHOLS.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 232,956 Fritz Oct. 5, 1889 979,934 Davies Dec. 27, 19102,090,639 Rose Aug. 24, 1937 2,153,462 Hauke Apr. 4, 1939 2,340,393 ByrdFeb. 1, 1944 2,461,008 Stearns Feb. 8, 1949 FOREIGN PATENTS NumberCountry Date 225,751 Great Britain Dec. 11, 1924 570,195 Great BritainJune 26, 1945

